Multi-tube effect of external condensation with non-condensable gas in a tube bundle

Abstract

The passive safety design concept is essential to remove decay heat under the station blackout. We conducted experimental and CFD-based studies on condensation in the presence of non-condensable gas to analyze the performance of a Passive Containment Cooling System. External condensation experiments were performed in 2 ∼ 4 bar, air mass fraction in 0.2 ∼ 0.7 with 1 ∼ 3 cylindrical tubes. CFD simulation was also performed to analyze the condensation phenomenon considering the effect of the tube bundle in terms of the ratio of Heat Exchanger area and vessel volume (A/V). We conducted the sensitivity study on the various tube bundle and vessel geometry by CFD and suggested bundle correction parameters as a function of the A/V. As a result, we evaluated the PCCS design with the horizontal tube bundle. It significantly reduces the required number of tubes compared to vertical tube bundle design because of the larger tube surface area and higher HTC by an inclination enhancement factor.